Early motor vehicle manufacturers offered only a limited choice of luxury interior options and concentrated primarily on refinement of mechanical and electrical operating hardware. However, as vehicle hardware entered an era of standardization, attention to improvement of driver comfort increased dramatically. While most passenger vehicles now offer numerous luxury interior options, trucks and other commercial vehicles are outfitted with very spartan interior accessories. Although a limited number of luxury trucks ply the highways, most truck drivers operate fleet vehicles on a daily basis. Fleet trucks are generally purchased in quantity by trucking concerns with an eye toward efficiency and low cost, so luxury cab accessories are deemed prohibitively expensive.
The typical fleet vehicle utilizes only a single driver's seat on the left side of the cab, or at most a pair of bucket seats mounted on opposite sides of the cab. A padded platform projecting normally outward from the door panel provides a resting place for the operator's left arm (or passenger's right arm). No such arm rest is provided for the operator's right arm (passenger's left arm), which must remain uncomfortably suspended next to the body for extended periods. During a full work day this position exacts a considerable toll on a driver's performance.